United States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
EPA/ROD/R08-90/038
February 1990
oEPA
Superfund
Record of Decision:
Rocky Mountain Arsenal
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REPORT DOCUMENTATION 11. REPORTNO. I ~ 3. A8clpl8nC'8 AcC88810n No.
PAGE EPA/ROD/R08-90/038
~ TII8... WMI88 5. Report Da18
SUPERFUND RECORD OF DECISION 02/26/90
Rocky Mountain Arsenal (Operable Unit 18), CO 8.
Third Remedial Action
7. ""00(8) 8. P8rformlng Org...lDtion R8pL No'
8. P8rformlng Org8lnIDtion "'1118 end AddNU 10. Proj8C1lTuluWortI Unit No.
11. Con1nc1(C) lit Gr8nl{G) No.
(C)
(G)
1~ ~ng Organization N8me end Adchs8 13. Type of Repor1. Period CO.....
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
IS. SUpplementary No..
11. Abnac1 (UnlIt: 200 _Ida)
The Rocky Mountain Arsenal (RMA) (Operable Unit 18) site comprises part of the
17,000-acre RMA site, which is a former U.S. Army chemical warfare and incendiary
munitions manufacturing and assembly plant in Adams County, Colorado. From the 1950s
until late 1969, the U.S. Army used the RMA facility to produce the nerve agent GB
(isopropyl methyl- phosphonofluoridate). In addition, between 1947 and 1982, private
lindustries leased major portions of the plant facilities to manufacture various
insecticides and herbicides. Since 1970, facility operations primarily have involved
the destruction of chemical warfare materials. Because final remediation of the RMA
site will take many years to complete, thirteen Interim Response Actions (IRAs) were
determined necessary prior to implementing the Final On-post Record of Decision (ROD).
Operable Unit 18 (Motor Pool Area) is one of several areas included in the Other
Contamination Sources IRA. The U.S. Army acquired the motor pool area in 1942, and used
it for storing diesel fuel, gasoline, road oil, and flammable liquids in an above-ground
storage tank farm. In addition, during the early 1950s, several buildings were used for
pesticide and herbicide storage, and later these buildings housed an agricultural
research and bioassay laboratory. The Army continues to use the area to service
(See Attached Page)
17. Docum8nI An81y818 .. o.-...~
Record of Decision - Rocky Mountain Arsenal (Operable Unit 18), CO
Third Remedial Action
Contaminated Media: soil, gw
Key Contaminants: VOCs (benzene, TCE)
b. 1d8n1l1l8r8l0pen.EncI8cI T-
Co COSATI FI8IdIGroup
18. Av8ll8bl11y ~ 1'. S8curt1y 0- (Thla A8port) 21. No. 011'811"
None 38
20. S8curt1y ca- (ThI8 P8ge) 22. Price
Nnnl'>
50272-101
(S. ANSI-Z38.18)
S. NItuctI- o..~-
(FOI'IMfIy NT1S-3II)
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EPA/ROD/R08-90/038
Rocky Mountain Arsenal (Operable Unit 18), CO
Third Remedial Action
Abstract (Continued)
equipment, vehicles, and railroad cars. A diesel fuel spill and other spills related to
piping from underground tanks have been recorded. In 1985, ground water monitoring
identified TCE contamination near the motor pool area and in downgradient water supply
wells. Records indicate that vehicle maintenance operations involved discharging water
and other liquids, and rust residues through floor drains and pipes into unlined ditches.
This ROD addresses interim remediation of source areas and management of migration. The
primary contaminants of concern affecting the soil and ground water are VOCs, including
benzene and TCE.
The selected Interim Response Action for this interim remedy includes conducting a vapor
extraction pilot test; installing and operating an in-situ vapor extraction system,
followed by granular activated carbon treatment of condensed water vapor with offsite
thermal carbon reactivation; capping the site with a layer of asphalt to improve the
efficiency of the vapor extraction system; conducting air monitoring, followed by
possible stack treatment by a vapor phase carbon filter or catalytic oxidizer; and ground
water pumping, treatment, and reinjection in conjunction with the Rail Classification
Yard IRA. No costs were provided for this remedial action.
PERFORMANCE STANDARDS OR GOALS: No chemical-specific goals were identified for soil
contaminants. Chemical-specific goals for ground water treatment, which apply at the
point of injection, are contained in the ROD for the Rail Classification Yard IRA and
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fINAL DECSION DOCUMENT
FOR nIE INI'EIUM RESPONSE AcnON
AT nIE
MamR POOL AREA
RCXXY MOUNTAIN ARSENAL
FEBRUARY 19IJO
OONTRAcr NO. DMAJ..S.88..D-0022/(1m
VERSION 4.0
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WOODWAJU).Q. YDE OONSULTANTS
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PROORAM MANAGER fOR ROCItY MOUNTAIN ARSENAL
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'tHE 1NFOltMA110N AND OON<1USlONS PRESENI'ED IN '11m REPORT REPRESENT 11IE
OFf1CIAL ruvnON OP THE D~ARTMENT OPTHE ARMY UNLESS EXPRESSLY MODIFIED BY
A SUBSEQUENT DOCUMENT. 'I1DS REPORT CONS'ITIUI"PS THE RELEVANt' POR110N OP 11IE
ADMINJSTRA11YE RECORD POR'I1DS CERaA OPERABlE UNIT.
THE USE OP TRADB NAMES IN 11IIS REPORT DOES NOT CONS'lTlUl'l! AN OPPICAL
ENOORSEMENT OR APPROVALOP THE USE OPSUOI COMMERaALPRODUcrs. nus REPORT
MAY Nar BE aTED fOR PURPOSES OP ADVER'I'ISEMENT.
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Woodward.Clyde Consultants
TABLE OF CONTENTS
lli1i2n fm
1.0 Introduction 1-1
2.0 Hi5tory or the Motor Pool Area 2-1
3.0 Interim Response Action Obj~ives 3-1
4.0 Interim Response Action Alternatives 4-1
5.0
6.0
/-..~
4.1 No Action 4-1
4.2 Monitoring / .. 4-1
4.3 Institutional Controls / I" '",- 4-2
4.4 Multilayered Cap / 0"', " 4-2
4.5 In-situ Vapor Extraction '........./' '" '-, 4-2
, '
4.6 OnsiLe Incineration .' ') ',. . 4-2
4.7 BioremediatioD.'/ 4-3
4.8 Low-temperature Thermal DesorptioD' 4-3
4.9 Of{site I,DciDeratioD ( 'VI 4-4
::ooo:o::::u"-- ~ ~":::v/9
Summary or the IDterim Respo~ ""~ - \ ~/ 6-1
\ \ , """"-J r------- " -:-.. 6-1
6.1 Healtb & SaCery Plan \'../ / ..\,~. ~
IDtcrim Response Acti98-~SS \.\ ~ \>.
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ARARs ,// /~ v ''''-,
Schedule " V / --- ',:
~ RelQ' ~ /j
1-1 DecisiOD ~ for lDte .
MoaitoriDa/MaiD DaDCC OD Hot
7.0
7-1
8.1
8.0
9.0
9-1
10-1
11.1
2-1
2-2
2-2
2-3
1-2 .
Locatioa Map - Rocky Mountain Arse
Motor Pool Area Vteiaity Map
2-3
TCE Soil Gas Sur.'CY . Motor Pool Area
2-S
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1.0
INTRODUCfION
The Interim Response Action (IRA) alternaoves a.s.sessment and decision process for the Motor Pool
Area at the Rocky Mountain Arsenal (RMA), is being conducted as part of the IRA process for R:-.iA
in accordance with the Federal Facilit)' Agreement and Tech.nic:al Program Plan.
Tbe determination to implement this action has been reached through a consideration of the objectives
of Sections 2.3(a), 22.5, and 22.6 of the Federal Facility Agree.ment and by application of the Decision
f10w Chart for Other Contamination Sources lRAs adopted by the Organizations and the State in the
June 7, 1989 Subcommittee meeting (Figure 1-1).
./ . ... ",
. "
'. "-
Alternatives have been reviewed based on their overall proted.iv~ess of human health and th::
....
environment; compliance to the maximum extent practicable with Applicable or Relevant and
Appropriate Requirements (ARARs); reduction ill ~obility, toxicity, or volume; short- and long-term
effectiveness; implementability; and cost-ef'r~~~~. The proposed$' will consist of ~e installation
of a vapor extraction system at an identified s~~ o!, trichloroeth ~ the M.~or Pool Area, to
remove and treat the soil contamiDattoe....Q.ther poteotial sources of gro~~toatamination at the
\ '
site will be contained by installing. iO\md~tercePti~ iinkr~ent 5)ue~ downgradient of
the Motor Pool Area. iD coDjunction\vit6 the Rail Qassi!icatiap ~ ~
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SITE CHARACTERIZATION
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NO .. /, "., MONITORINGI
OR DATA INADeQUATE <~, MAINTENANCE
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1-2
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Figur. 1-1'- DECISION FLOW CHART FOR
INTERIM ACTION VERSUS
MONITORING/MAINTENANCE IC~
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Woodward.CIyde Consultants
2.0
HISTORY OF nm MOTOR POOL AREA
Rocky Mountain Arsenal (R..\.iA) occupies more than 17,CXXJ acres (approximately 27 square miles) in Adams
County, directly northeast of metropolitan Denver, Colorado (rtgW'e 2-1). The property was purchased by the
US government in 1942 for use in World War II to manulact\jJ'e and assemble chemical warfare materials, such
as mustard and lewisite, and incendiary mwUtions. Start.ing in the 19SOs, RMA produced the nerve ageot GB
(isopropyl methylpbospbonofluoridate) until late 1969. A significant amount of chemical warfare materials
destruction took place during the 19505 and 1960s. Since 1970, RMA has primarily been involved v.ith the
......
destruction of chemic.a1 warfare materials. In addition to these dtary activities, major portions of the plant
facilities were leased to private industries, including SbeU Oil' a:>mpany, betWeen 1947 and 1982, for the
manufacture of various insecticides and herbicides. / /~., .~,
~ 'v' '''''~
The Motor Pool Area is located in the soutbeastern ~r of Section 4 ~the RMA. The site was acquired
,
by the US Army in 1942 as part of RMA. and it has..bcri used since tbe 19405 for servicing equipment, vehicles,
I I /'.
and railroad cars, as weU as for storing fuel, road ;w,:aD9'lJ.a%nmable liquids. rtgW'e 2-2 sbows'tbe Motor Pool
Area. ~ ~ j)
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The site was surveyed in 1986 for rece~~e (TCE~c.ause tad been found in
\\ I ,I. v
groundwater monitoring wells Dear the Motor ~apr~~d in downgr~~ ---. unty water supply wells.
in 1985; however, DO TCE use was found. Records mdic.ated, however; the s.dtveDts probably were used for
....--... , " .
cleaning and repairing equipme~1Dd tehides iD ~diDgs ~diDg tbe Motor Pool Area from the early
I ,. ,,", ,
1940s until at least 1985. ¥&ics, ruSt ~ fuel. oil. and F~~~re ~used, and metal surfaces of the
equipmeDt and vehicles weie ~~ed thero; ~me ott!l?b~diDgs were mown to discharge water
and otber liquids and residues (r~~ maiDte~c~~~iac.i~ns through floor drains and pipes into unlined
d;,ch.5. Th. M"'~~ ,iI..h use for ""'~~aikar .....,....cc (Ebasco 1989),
AD above-grouD ~lJe tuk\ in the rn pan ~otor Pool Area has beeD used since the early
19405 for storage ~~ psoliD rd' d draiD oil. There is record of a break in an uDderground
line coDDeclina these 0 the semcc 0 the east, c:reatiD& a diesel fuel spill Other spills related to
piping from UDderp'OUDd tub aDd tanker tru U\'e also occurred in the service statioD area (Ebasco
1989).
In the early 19SOs. seYCru buiJdiap in the Dorthern part or the Motor Pool Area were used for pesticide and
herbicide storage. During this same period, Julius Hyman and Company operated laboratories for the study of
iDsec1icides and plant pathology Dell' the southern pan of the Motor Pool Area. SheD Oil Company took over
2.1
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WELD CO.
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ADAMS CO.
ARAPAHOE CO.
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ICAU IN MILoU
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10/21/88
Figur. 2-1 LOCATION MAP
ROCKY MOUNTAIN ARSENAL IIT~
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. 532 BUILDINGS
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STORAGE TANI(S I!'./
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SOURCE:EBASCO. MOTOR
POOL AREA
CONTAMINATION
ASSESSMENT
REPORT. 1988
Job No. I 2223.
",,"red ..,: D. C.C,
Do.. I 10/23181
Figure 2-2 MOTOR POOL AREA
VICINITY MAP
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Woodward-Clyde Consultants
these facilities in 1953 and maiotaioed an agricultural research and bioa.s.say laboratory there until 1957 (Ebasco
1989).
Two soil gas surveys were conducted in the Motor Pool Area in 1986 to aid in denning any plumes of TCE
contamination in the groundwater. The studies defll1ed an apparent TCE soil gas concentration in the area north
of the roundhouse (Building 631) and a soil gas plume extending northwest Crom the site (Ebasco 1988).
Another soil gas survey conducted in July 1989 traced the TCE source to an area adjacent to Building 624 where
a pipe from a floor draio was found to discharge into a ditch (WCC 1989). rtgW'e 2.3 shows the soil gas plume
that was used to defll1e the source area. For evaluation purposeS, the extent of contamination has been
considered to be a 60 foot by 100 foot source area bound on ~ .DOrth and south by Buildings 624 and 625.
respectively; on the east by tbe walkway betWeen Buildings 624'aad 6~ ~d on the west by tbe rail spur. It was
estimated tbat approximately 4,.soo yd3 of soil would be ~dressed.b~'this IRA, for the purposes of the
alternatives assessment. /'/ ""v I
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On February 1, 1988, a proposed CODSCnt Decree wuJodaea in tbe casc of United States v. Shell Oil ComDanv
, ......... .
\\lith tbe US District Court in Denver, Colorado. '''The ~posed Consen ee was revis~ after public
comments were received, and a modified pr:.C?posed Cons~t.D'a,ee was lodged .tJ1 e C ;t,.O~ June 7, 1988.
. -- 'v ." I
In February 1989, a Federal Facility ~~-~ntered i11~tWeen ~/deral agencies: the
Environmental Protection Agency, the Army. tb~ ~~-artlllent of the ~n~~artment of Health and
Human Services, and the Department of Justice. which estab1ished pr~~plementing the Arsenal
cleanup program as specified iD'~Cchnical P~ Plan ibcI incorpo'tu"csl the modified proposed Consent
. .~ ""-' .
Decree. The Army and Sb~U.Oil Co~paRy.~d to share cenaa~ of tho ,!.mediation to be developed and
performed under the overslJbt~Jlae. t1S"EavirOnment~ PfoIedio. ..~ with opponunities for participation
by the State of Colorado. TherOll8:t~ remediation is.,~ tisTt1ilt wiD take several years to complete.
The Federal Faci1i~~e. s~ 13 IDte,.~,~~~DS (IRAs) determined to be necessary and
appropriate. ne- emediati' ~ Other Conuminatio ~ces~one of the 13 IRAs. The Motor Pool Area
;'_ofm.~-
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FIGURE 2-3 TeE SOIL GAS"
SURVEY MOTOR POOL AREA
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3.0
INTERIM RESPONSE AcnON OBJECI1VES
The specific objective of the interim response action (IRA) at the Motor Pool Area is to mitigate the threat of
releases of volatile organic contaminants from the Motor Pool Area on an interim basis, pending determination
of the final remedy in the Onpost Record of Decision (ROD).
The IRA alternatives have been evaluated based on the following aiteria:
Overall protection of human health and the en~~ent
Compliance with Applicable or Relevant and APi,>ropriate Requirements (ARARs) to the
/
maximum extent practicable :' /'...., ~
Reduction of mobility, toxicity, or volume V '-''''''0
. Short- and loos-term effectiveness ,1/;
. Implementability / /
. Cost (' (~/) "
"-....' <. /.... /)
.......... " '...."""""""',' ,/
This DecisiOD Document provides a sum~ the alterDlt~ technologies cO.$id~i ~oDology of the
significant events leading to the iDitiatioD( <;>f ~.~ary of IRA pro~? a summary of the
ARARs (legal and regulatory standards, ai~~~,er 1iDi1tariODS) . t~ ogram.
\,:,/ \/ ,
As specified in the Federal ~a~eemeDt.. ~ IRA ,~~ tre~~t of soils and CODtainment of
groUl>llwater. to Ibe maxim"" V~ be eotWsteDl . U4... coatriI?ote to Ibe efflcieo. perform an,"
01 the Final Respoose A. ~ ~ "-,
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4,0
INTERIM RESPONSE AcnON ALTERNA TTVES
Alternatives were examined in tbe "Alternative As.sessment ofInterim Response Actions for Other Contamination
Sources-Motor Pool Area" (WCC 1989). These alternatives included:
. No Actioo
. Monitoring
. Institutiooal Cootrols
/'
Multilayered Cap. . '
.
. lo-situ Vapor Extractioo. "
I" ...
/ " "-.
. Onsite Incineratioo. /
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Bioremediation .,
, ..
. Low-temperature Thermal Desorptioci~/
. Offsit. ID
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Woodward.Clyde Consultants
4.2 MONITORING
This alternative consists of conduct.i.og upgradient and dOWDgradient groundwater sampling. This aJtercalive
would Dot reduce contaminant mobility, toxicity, or volume. Monitoring would allow coDtinued tracking of
contaminant movement.
4.3 INSTITUTIONAL c(\JlrJ'ROLS
This alternative consists of constructing a chain.link fence with coDtroUed access points around tbe area of
concern. This alternative would not reduce contaminant mobility, ~~city. or volume. Since RMA already bas
limited access maintained by physical barriers and security persoaDei, additional site .restrictions alone would
be of limited effectivcncss. // /'.".,"-.."
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This alternative consists of constructing a multilayered ~1.'~r the contaminated soils in the Motor Pool Area.
The cap would consist, from the base upward, of ia.~8.~ch-thick layer o~ permeab~~y, a nexible
membrane liner, a synthetic drainage net, ,a geotextile mi~c; aud a 1-(oOt~~./e/IoW1ayer. The cap
would be sloped (rom the center to fa~t~. r. The cap ~ ~~oDtinued downward
m;gralioo 01 ,oot......... to the gr~odWal~r:~<,..... au uu~~
This alternative can be easily ~~*d because,it is based. demo~ecf, technology that has been widely
used. The long-term effecti~noSs o!)biS.~tive is some~' . d bel'~~ it is a CODtainment technology
that does Dot aduaDy re~" ~urce 01. . a, This alternative would not reduce
contaminant toxicity or volWD~t it' ~uld reduce mo&~ ~ - utioa would be necessary to assess
the oootUoued e~\bis ~~ ~ ~
4.5 IN-SITU ~ ON 1 ~
4.4 MULTIlAYERED CAP
This alternaiM coDliits pot extrlCtioa syaem to Ileal the coatammated sOils in the
UDSahlrated (vacbc) lODe of the Motor Pool vapor CIU'ICtioa proc:cu consists of applyin'l vacuum
to a weD or tIeDcb lCreeaed in the zone of co 'oa. iDduc:iq a flow of air throup adjaceat soils, and
progressively 1ir.1IIWia8 the "OIatiJe contaminants coataiDed in the lOillIWriz. The CODtamiDuts are then
adsorbed oato aClivllcd wboa aDd deatroyed wbca the cuboa is thermally reactivated off site,
This alternative CaD be easily implelDWed because it is baed OD delDoastrated techDoJOI)' ud has beea widely
used. The system CIa be easily adapted to a Fearer depth or exteDI of CODtamiDatioD, which is important
(11111C112..woo) (mocor~) (11f21/19) (RNA)
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Woodward.CIyde Consultants
because of the uncertainties in contaminated soil volume at this site. Also, when the carbon is thermally
reactivated, the contaminants are destroyed.
A groundwater interception and treatment system would ilio be implemented as part of this alternative to
contain groundwater contamination from possible contamination sowces not identified in time for this IRA:
Groundwater extracOon wells would be located Dorth-northwest of the Motor Pool Area. Extracted water would
be sent through conveyance piping either to the lrondale Containment System, which would be expanded to deal
with the increased flow, or to a treatment system built to treat extracted water from this IRA and the Rail
Classification Yard IRA.
.~
4.6 ONSITE INaNERA 110N
, '
This alternative consists of excavating the contaminated soils in the Motor Pool Area, incinerating the soils in
a mobile rotary kiln incinerator, and placing the treated soil back into the excavation. This alternative completely
destroys the organic contaminants that are a concern at the Motor Pool Area.
. ~V)
, / ....
Altbough this alternative has a good long. term effea,iveaess because it destroys the cont4mJnants. onsite
, '
incineration is more difficult to implement th~ other alternati..v~ because of thc'com~x ~cbanical operation,
monitoring. and control to maintain high de~r~ D4..r~~~ effi~~ This IRA ~aJtt;native is also very
costly relative to other treatmeat alternativeS. V/r---/ \ ~ -----.,
\... '\.'--
\ .'. '... .
A gr~und~ater ~terception ~G; , ~nt systc'm. 'would ~~~ ,imple~cnred as part of this alternative, as
described 111 SectIon 4.5. / ;' ,----. "', '.
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4.7 BIOREMEDIA110N." "'.... "'..:;:::..--
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This alternativ~'~ of eXca~ the ~~iJ1at~~ tk' Motor Pool Area and treating them with
bioremediatio~~vated sJ~ed d be (Jd ~ conveyor to"'q. 'laitltiOD vessel where the soil would be mixed
with water and a co~~ Slurry ~. ". The slurry would theD be transferred to a series of
liquid/solid coatact bior '" n wbcrc . at aDd autrients Ile introduced to maintain the biodegradation
of the organic c:oatamiDaDts in tile soiL This . destroys the orpnic coDtaminants that are a concern
at the Motor Pool Area.
This alternative bas lood IOIll-tena dfec:tiveDess because it deslroys the COfttAmil'llftts. However, there are some
uncertainties in bioreactioD rates ud raeatioD times that could affect the schedule. Also. there is some potential
Cor the leDeratioD of partial deandatioa products such u dicb1oroethytene and vinyl cb1oride. Because of the
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Woodward.CIyde Consultants
uncenainties in the depth of contamination, modified excavation techniques may be required, which could affecl
costs.
A groundwater inter~ption and treatment system would also be implemented as part of this alternative, as
described in Section 4.5.
4.8 LOW-TEMPERATURE THERMAL DESORPTION
This alternative consists of excavating the contaminated soils in the Motor Pool Area and treating them with
low-temperature thermal desorption. Excavated and saeened soil would be sent to a low-temperature thermal
stripping processor or a rotary drum system that heats the solids to about 400 . F and vaporizes the contaminants,
Particulates would be removed from the contaminated vapor~ ud theu the vapors would be condensed. The
condensate would be sent to a solvent/water separator and oDlo carbon flltccs. The clean water would be used
for dust control during excavation, and the gases would be sent to an afterbwrner. This alternative completely
destroys tbe organic contaminants that are a concerD II the Motor Pool Area.
I' (. /)
" ....",
This alternative has good long-term effectiveness 'becaus~ it destroys th~ .c:optaminants. ,Because of the
... ",- " " , /
un~rtainties in the deptb of contamination, modified excaVatioD techniques matbe'te.Q.uired. which could affect
costs. (~V ( ~/
\\/.~, \~
A groundwater inter~ption and treatment syStem would also be imptemcnted as-paft of this alternative. as
de.cribed ill SectiOD 4.5. j=)' . . . .;
490FmT£~W~' . ~~/
~ '- ". "
" '. .... .'.',
This alternative co . t e vatiDa~taminate4 'Soil in 'the Motor Pool Area and transporting the soils off
site to aD exi.stf(permitted \. dous Wast1~~~'~~~ernative completely destroys the organic
CODIaIDioaots ~II the M ,6r}/ool Area. "'-.) .
This ah.....u.. boo ~..... ee . ~ k datroys the COIIWIIiaaDts. There could be some
~ associated wi1b trusportatioD. Also, beca~ ~e uncertainties iD the depth of contamination, modified
excavatioD tecbDiques may be required. which coul eel costs. This altema~ is very costJy relative to other
treatmeDt lltenatMs.
A p'0undwater iDtercept10D IDd treatment system would also be implemented u part of this alternative, as
described iD Section 4.5.
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4.10 CONa.uSIONS
Installing and operating an in-situ vapor extraction system is the cbosen alternative. This alternative can be easily
implemented because it is based on demonstrated technology and bas been widely used. The system can be
easily adapted to a greater eXlent of contamination, which is important because of the uncertainties in
contaminated soil volume at this site. Also, since the car~n is thermally reactivated, tbe contaminants are
destroyed.
A groundwater interception and treatment system would also be implemented as part of tbis alternative to
contam groundwater contamination from possible contamination ~s not identified in time for this IRA.
/ ,
/' ,.
, "
Installation of an in-situ vapor eXIt action system and groUDdwatcr interception and treatment system will
effectively mitigate future potential contamination migiM;on fr~m ~e Motor Pool Area. Therefore.
implementation of this action now will yield both a CO$( :and techn.ica1 benefit and will be consistent with and
contribute to tbe efficient performance of the fmal response action.
/(/1
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5.0
CHRONOLOGY OF EVENTS
The significant events leading to the proposed decision to remediate soils in the Motor Pool Area as
described in Section 6.0 of this report arc presented below.
Dale
E~
January 31, 1989
State of Colorado, SheU Oil Co., EP A, and the Army develop and agree in a
JUDe 1987 report to the court to (,rospective bot spot list which identifies
Interim Response Actions (IR.AS)to be cooducted. The hot spot list consists
of five arus (the Sectioo. 36 T'reDcbc~ the Section 36 Lime Pits, the M.1
Settling Basins, the Motor'Pool Area; IUlchhe Railroad Housing Track in the
Rail Classification Yard) referred to as .Other CODtaminatioo Sources" in the
proposed Conseot Decree (SectioD 9.1, paragraph I), and in the Federal
;'; ~........ .
Facility AgreemCDr, paraVaPh 22.1 (I).
" v <. ~ /')
The Sta~c...of COlora~~/Oil Company, amt EP~e/i:m{;a1IY requested
tOideDt~\~S for~\ . ~/
\ \, , ., ~
\ ~ . ~ 7
The Army mstnlcts Woodward.Clyd~~~WraD'tsiWCC) to develop plans
. ~\erim acticm investiga~OD~ork in ~&Spoose to the bot spot list. In[erim
/ / .~n !Uwcs~ati~n work iDcl~e MOtcv Pool Area.
~V r----'.. '"", ¥ .
April 13, 1989 ~ ~ Task PI~ wfUch ~udes the Motor Pool Area, is submitted by the
>\ ~!be Or~~ Statc (or ",....c.t.
ApriI'''- 'i.~ FIOId m#tioDs ~ DIhcr ...........tioD sources IRA, W.,k
~ 01 !be a>DIIIIIiDaDl source(s) withiD thc MolO' Pool
A fiDa1 Task Plan 15 issued by the Army with comments incorporated.
JUDe 1987
February 1988
June 29. 1989
July 20, 1989
f'teld iDvatiption completed.
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November 27, 1989
November 27, 1989
November 27, 1989
February 1, 1990
March 5, 1990
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Woodward.CIyde Consultants
Draft rmaJ Results or Field ud Uboratory InvestjptioDS Conduded (or the
Remediation o( Other Contamination Sowc.cs Interim Response Action is
distributed by the Army to the Organizations and the State.
rlDal Alteruativea ~ssmeDl o{ Interim Response Action {or Other
Contamination Sowces - Motor Pool Area is distributed by the Army to the
OrganizatioDS ud the SWe with respoosea to comments iDcorporated.
Proposed Decision DocumeDl {or the ln1erim Response Action at the Motor
Pool Area at the Rocky Moumam Aneaal is distributed by the Army to the
QrganizatioDS ud the SWe {or COIIUDenL
Draft F'mal Decision DocwneDl {or the Interim Response Adion at the M~tor
Pool Area at the Rocky Mountain Arseaal is distributed by the Army to the
OrganizatiODS ud the State.
Decision DocumeDl {or the Interim Response Action at the Motor Pool Area
at the Rocky MOUDlIiD Aneul is f;,ulli,_A .
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Woodward.CIyde Consultants
6.0
SUMMARY OF THE INl"ERIM RESPONSE AcnON
Installing and operating an in-situ vapor extraction system in conjunction with a groundwater interception and
treatment system is the chosen alternative. This alternative can be easily implemented because it is based o~
demonstrated technology and has been .widely used. Tbe system can be easily adapted to a greater depth or
extent of contamination, wbjch is important because of the wu:ertamties in contaminated soil volume at this site.
Also, since the carbon is thermally reactivated, the contaminants are destroyed.
or- ,
This alternative will involve installiog several extraction wells or treaC:bes in the area of contaminated soil at the
Motor Pool Area. A pilot test will be performed before iDstallatioa (0 determine the well locations or trench
size necessary to capture contaminants through the areal e~s ~'~~p~e. Tbe site will be capped with a
layer of asphalt to improve the efficiency of the vapor e~~ctioD process>~ssurized and possibly pre-heated
air will be injected into the soil. Soil vapors will be drawo by a positive displacement vacuum blower through
..' l
an inlet liquid separator/silencer, which is insulate,," ~ muffle expanding gas DOise. Stack discharges will be
." I)
monitored and regulated to maintain a volatile o~ ~issiOD rate belo~dard emissi~ limits. An
automatic shut-off will be installed in the stack moDi~ <"'~em to shut off ~~m 0-ilsions reach a
coDe"'trali.o above tho Standards. ~ ~ . ~
Stack troalO1oo, may be occessary dopcodiq WoI';t"aod Startup ,~ or exhaust air can be
routed through a vapor phase car~~er or ca'~NC oxidizer to adsorb 'Oo!~ "; IZe volatile emissions from the
exhaust prior to discharge to t)a~e m~p"ere. ,) ... \
/ -~ \}
Any liquid collected or CODde~/tbe inlet/silen wo osist red ioaotly of condensed water vapor
from the soil gas. . r wo r . e trea~p disposal. A1J applicable treatment would be
granular activ~~ed D. e pent bon woul . SU Dt reactivation. The volume is expectcd
to be very low.
There may also be of II' ntami-bon in the Motor Pool Area that have Dot been
clearly cSefiDcd in lime (or dais IRA. ID ° addresa these other potential sourc:a, a groundwater
interception aDd UClbDeDt system would be imple The P'ouodwater would be intercepted by extraction
wells that would coDect the cootaminated P'0uodwater ad retard the prOFCSI of the plume. The extraction
wells would be 10cated DOrth-nortbwest of the Motor Pool Area aad would be desiped to extract approximately
100 to 1SO GPM. The exact 1oc:atioo ad extractioo rate would be detUIDiDed during the implementatioD phase.
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Extraction water would be treatc.d in conjunction with the Rail Classification Yard IRA. Water would be sent
through conveyance piping to the lrondale Containment System. which would be expanded. if necessary, to deal
with the increased flow. If the Irondale Containment System cannot be adapted to deal with the increased now.
a treatment system would be built in the vicinity of the Motor Pool Area IRA and Rail Classification Yard IRA
eX1Iaction systems.
6.1 HEAL m ck SAFETY Pu.N
A Health'" Safety Plan has been developed for the prevention of occupational injuries and illnesses during field
aC1ivities at RMA. This plan addresses health and safety requirements of contractors and their authorized
I , .
subcontractors. Compliance with this plan will be compulsory, uC! the contractors will be responsible for self.
I {
enforcement and compliance with this plan. The Health '" Sa,krv..Plaa. was developed taking into consideration
I -" -', .
" .
known hazards as weD as potential risks. Comprehensive eia)'ilomnenW m~nitoring and site.specific personal
protection are combined in an effort to best protect :7/'r5. "--V'
//
, A site.specific Health'" Safety Plan for work to ~ ~ in the Motor Pool Area will be developed and
included with tbe dcsip spccificalioo pacbp. ~ v
~~
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7.0
INTERIM RESPONSE AcnON PROCESS
Witb respect to this Interim Response Action (IRA) (or the remediation o( other contamination Sources,
including tbe Motor Pool Area at Roclcy Mountain Aneaal (RMA), the IRA process is as (ollows:
1.
The scope o( the IRA is described in the June S, 1961 repon to the COW1 o( the United States
' ,
(the Army and EPA), Shell. and the State in, Uaited States v. Sbell Oil Co. A similar
/ ,
description is iDcluded iD the proposed Conseat Decree, paragraph 9.1 (1), and in the Federal
Facilil}' Agree..e.. (FFA), paragraph 22.1 ~
If any Organization identifies any ,Id~onal source areas (or iDclusion iD this IRA, the
.. /
Organization may submit to the (oth.~s I.written repon identifying the source area proposed
lor iodusio. aDd setliog lorth the'~hoical, and sa Iifi< hash I", ij,"POSaI.
Within 30 days after thC"5D~n ~eport, the Army ermiDe wbether the
source area should be ~~ ~ aDd ~u, EP , /d the State of its
deter:miDatioD: If SheD o~ ~A.~~ with the d ~~ 0 e Army, Sbell or EPA
may lDvolte D~~SOlutl0D.\ ": \ ,-
~/'.. . ''0' (", '. \
The Arm , ~~ State .~ n~ty to ideDtify, on a prelimin~ry
has;" any "~ijcahle '" R~aod ~e Require..e... (ARARs).
,?~ ~oposed ~~~ ~ lor the IRA lor the ioterim re..edia,;o,
<.. aI'"other COD \ 'OD sour otor P for a JO.day public comment period. During
1tsc y eDt pc . Army wiD public mectiDa addressing the IRA decision.
This Decisio t is supported by aD administtative record.
2.
3.
4.
5.
6.
Promptly after the dose of th ear period. the Army shaD transmit to the other
OrpaizatiODS, DepartmCDt of lDterior (DOl). IDcI thc State. a draft fiDaJ IRA Decision
. Documcnt for the remediatioD of othcr contamin.tion sourc:ea. Motor Pool Area.
7.
Within 20 days after the issuance of a draft &aal1RA Decision Document for the iDterim
remediatioD of other CODtaminatiOD sourcea, Motor Pool Area. an OrpaizatiOD (iDcludiDg the
(11111~) (lIIOCor.7.in) (11/21/89) (RMA)
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Woodward.CIyde Consultants .
State if it has agreed to be bound by the Dispute ResolutioD process, as required by the FF A,
or DOl under the provisioDS set (orth in the FFA) may invoke Dispute ResolutioD.
8.
After the close of the period (or invoking Dispute Resolution, if Dispute ResolutioD is DOl
invoked, or after the completioD o( Dispute Resolution, if invoked, the Army shall issue a fmal
IRA DecisioD Doc:umeDt to the other OrganiutioDS, DOl, and the State. The Army shall also
DOtify the public of the availability of the fiD.aJ IRA DecisioD DocumeDt with the supporting
administrative record. Ooly preliminary desip wor'k (or the IRA may be coDducted prior 10
the issuance of the fical IRA DecisioD Docume6t./
. . /" ""'-. .
/ / "" . "
The IRA DecisioD DocumeDt for the rem'ediatioD actiVt"ty,of the Motor Pool Area ~ill be
subject to judicial review in accorda.o~ ~ SectioD xxXix ~f the Federal Facility Agreemenl
except where such review is ban~ by Sections 113 and 121 of the Comprehensive
,
EnviroomeDtal Response, Compensa~'Ud Liability Ad of 1980 (CERCLA), as amended.
42 U .S.C. Sections 6913 and 9621~"'-... ~~ <.:''''-.. //
V'" "'-. //
FoUowing issuaace of t~~~OE. ecisioD DOC~. eDt, the ~ be the lead party
responsible for designing \~.", jID~ .the tv A..~ aace with the Decision
\ /, ~
DocumeDt. The Army shall issue a draft IRA Implemeatacio. Do'CbteDt to the DOl, the State.
aad the other 9tP~ioDS for'l"t~cw aad COIfbDeut. The chalt'implemeDtatioD document shall .
.' Ow ""-
include flD~(cIfa~ ~~cificatioDS, f~1I... ~ anaJyais, a cost estimate, and IRA
dead1ines~r'¥IIICiitItioe-6f the IRA. ~ . "... .
"'-..., (. ~ ~
If aD~,~tio~~diDg thO~~ ~ ~'DOI, believes that the IRA is being designed
/,r -' ~'
. ~'Or1mPlemeD' iD I ma.aner~t . t -6bjec:tivcs for the IRA set forth in the final
~ Decisio eat, )lotherwise D . properly implemented, it may so advise the
rec:om e b e IRA should be properly deaiped or implem~Dted. Any
or (mdudiaa e, it it bu Ip'ecd 10 be bound by the procesa of Dispute
RcsoJuUc.. u required by the or the 001 UDder the cirCWDStaDceS defmed iD tbe FFA)
may ilM>te Dispute Resolution 10 the disaareemeaL
9.
10.
11.
12.
AI Lead pany for the desip and implementation of this IRA. the Army wiD issue the fmal
implemeDlaboa doc:umeut, u deac:ribed abcM. and wiD be respoasible ror implemeDting the
IRA iD accordance with the IRA Implementation DocumeDL
(11111CD2~) (1DOIDr-7.in) (11/21/19) (RMA)
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Woodward.CIyde Consultants
8.0
APPUCABLE OR RELEVANT AND APPROPRIATE REQUIRa(ENTS
FOR 1HE REMEDIATION OF OTHER CONTAMINATION SOURCES - MOTOR POOL AREA
INTER.IM RESPONSE AcnON
8.1 INTRODUcnON
These Applicable or Relcvu1 aDd Appropriate RequiremeA1l (ARARs) addreu the Rocky MoW11aiD Aneul
(RMA) Motor Pool Area. which baa bccD idcDtificd for rcmcdWioa prior to the wuuce of . Rccord of
Decision (ROD) for the ODpost Operable Uait of the RMA. The ldected altematiYe to aa:omplish this interim
remediatioD is iD situ vapor eJtrlcbOIL Tbi& ac:sioa is DQI the &aa1 rclpoaac ICtioD but ID iDterim ICtioD to
address this CODtamiDatiOD source prior to the issuance of the 0Dp0It ROD.
8.2 AMBIENT OR CHEMICALSPEaPlC ARAJtS
AmbieDt or chemical-specific requiremeDts set COIICeouabOD timitI or fIDICI iD various eDwoameDtal media
for specific bazardous substaDces. poDutaDts. or CODtamiDaDts. Such ARARa either set protectM deuup le~1s
for the chemicals of CODCCro iD the ck"'pu'ted media or iDdicate aD appropriate ~ of discharge based OD
techDolQlica1 coosideratioas.
The objectives of this interim respoase ac:tioD (IRA) are ~~ iD the Filial Altel'Dl1Ma AIK"",eDt
Document aDd this F'maI DecisiOD Doc:ument. This IRA wiD be implemeli1ed prior to the fiDaI remediatioD to
be UDdertakeD iD the CODtCII of the ODpost Operable Uait ROD. 1'be primary coot.",i"."t of coaccro for this
IRA is trichloroethyleDe (TeE), . ~ orpaic compoaDd. The media of caICCrD bue are sublurface soils
CODtaiDiDg volatile orpDic coat.",i"."ts. primarily TeE. HCJMVa', DO ambieat or chemical-specific ARARs
were ideDtified CODCCrDiD& nil of COII'8"'",8"'. far IOiIL 'I'1Iia IRA ia apec:ted to tab advIDta&e of
sroUDdwater tr~tmeDI provided tbroaP the IRA adcIressiDa the Rail ~.uifWtio-t Yard aDd datmic:aJ-specific
ARARs CODc:enUDa water trcaICct by that IRA. iDchactiDa WIler rec:cived IrCD the plume related to the Motor
Pool Area. U'e CC)ftt.i-t ill that Faaal ~ Documeal It ia ~ tbIIa separate ays&aD for poactwacer
treatmCD1 wiD be CGIIIInJCted far tbillRA. The filial Deciaioa DoaaDait for the Rail O,-i~tioR.YardlRA
coDtaiDs the ."ow &cuuioa of cIaemicakpeci& ARARI far poaadwlla tre.abDCIIL The ItaDdarcla ideDtified
below wiD ."., II die paiat of reiDjecdo8 of treated poaDhlter from tbe arOUDdwater trcatmal system
implemeDted pw'-' to dIia IRA:
Beazeae
~l-dich1oroed1y1a
1.2-dichlaroedtyleae
T -1.2-dicIIIoroe&hyleae
5 .".
1 111/1
10111/1
1 111/1
. &aIIuI
40 a:'IlI141.61(a)
CBSG
CBSG
40 a:'Ill 141.61(1)
ComDmIIMI
ARAIt. Uw.t
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carbon monoxide, ozone, nitrogen oxide, and lead and are nOt anticipated to be contained in any potential air
emis.s.ioDS, and these standards are defLDed in terms o( measuremenU in large air masses, so they are not
considered relevant and appropriate to apply to the type o( emission source that is intended to be utilized in
the context o( this IRA.
The standards contained at 40 CFR Parts 60 and 61 were reviewed and determined not to be applicable to
operations conducted as p".rt o( the treatment by this IRA system. These standards apply to specific sources
o( the listed pollutanu. for example, Subpart E o( 40 CFR Part 61 applies to 'sources that process mercury ore
to recover mercury and other specific processes, and the arsenic provisions o( Subparts N, 0 and P o( this part
apply to very specific plants, smelters or (acilities. Since the oper.a~ contemplated by this IRA treatment
system are extremely diWmilar (rom the processes desaibed in :40 cFR Part 61, these standards were also not
" "
considered to be relevant and appropriate to apply to this ~ triatment system. However, as discussed in
.',/ " "
Section 3 concerning action-specific ARARs, the Army wiH apply best practicable control technology to air
emissions (rom treatment processes. .II) ''''-v''
" /
." I
. I
. 8.2 LOC'.A 110N-SPECIfJC ARARs (.' '<....~/)
Localioa.spedlie require.,,,.. set ..stricti... o. a::m'tie...~odiag o. thc("~~...cr;,u." ~:e site or ,he
~ '.....! " ,,/./
immediate environment, and function likl, a~~qwreme~ts. A1ternative~a1~.saal actions may be
restriCled or precluded. dependiq on the ldea'tioa, or cbar.acteristic 0(~.1 ''-a ~De e requirements that apply
\'/ .\~~
to it. \ . :' \ '. /"-'
, \ ~ I
II should be ...ed that par,.~ ~~~ Facilil)' ~" ~~~ IIIaI "wildlife babitat(s) shall
be preserved and manaaecf-. ~Q(ect eDdupred ~()f ~dliCe to the extent reqwred by the
-, '" . ,"
Endangered Species Act (16 ~i.S31 GUCg.), aUgrMQty ~:.~ ClIent required by the Migratory Bird
Treary Act (16 U.S.~.), ud~&8Jd eagle&~~ ~ed by the Bald Eagle Protection Act, 16
U.S.C. 688 . . / \ " -" ~
WbiJe Ibis pr~ ~ r' 51. OI'J requiremCIIIS that arc _cd ARARs aod otMously
must be complied wUh of 011 where aDY treatment system is likely to be located,
the Army beIieva that this IRA wiD have DO impact OD aDY cad."Ffed species or misratory birds or
on the protecdoD of wi1d1ife habitats. CoordiDation be maiDtaiDed with the U.s. Filii and WlldliCe Service
to ensure that DO I1ICb adverse impact arises &om implementaboa of tbia IRA.
The Army c.oDSiders the prOYisiou of 40 CPR I 6.302(a) ud (b), CODcemiDg the location of aDY treatment
sysIem aDd avoidiDg the c:onstrUCtioD of such system ill a muner that would have an adverse impact on wetlands
or be withiD a Oood plaiD, relevut aDd appropriate to apply to the CODStI'UctiOD ac:tMties CODcenUng this IRA.
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The regulations in 40 CFR 230 were reviewed and determined not to be applkable withiD the conteXI of this
IRA because no discharge of dre4ged or nlJ material into waters of the United States is contemplated. Because
these regulations address only the disposal of such materials into the Waters of the United States, whjch is not
contemplated, they are not considered to be relevant and appropriate to apply in the conteXI of this IRA:
The regulations in 33 C~ 320-330 were reviewed and determined to be neither applicable nor relevant and
appropriate because they address actions aB'«:ting the waters of the United States. No such actions are
contemplated within the contell of this IRA.
,r-....
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Performance, design, or other action-specific requitemCGLs set coDtrols or restrictions on activities related to the
, management of hazardous substances, POUutants,/,~"~Dt~inaDLs. These action-specific: requirements may
specify panic:uJar performance levels, actions, or t~l.s as weD as S~J~ evels (or a ai~odology for
setting specific: levels) for discharged or r7,siduaJ C:hemic:ab:~ //
\\'-, ~ /
CQDltructioft of Trealtlt;DI S"'~m '\ . :\7
Air Emissions ~\. ~ \,
~J')~ ,)
On the remote possibiliry ~eri Ill'aYbeiir'emissio~e-c:CJurse of the construction of any treatment
system, the Army bas reviewed ~tiaJ ambieDt or 'Chcmi~specific air emissioD requirements. As a result
of this review, th.~~;-~,tJw ~e are, at A~~Ct~~ or State ambient air qualiry standards
currently appli~ or re~ ud approatiMe to : th~1ati1e or semivolatile chemicals in the
T~-~ //-,
grouodwater foDid ~ Vi' wtUcb . cUOD is COD lated.,
ID the CODtext of this is oaJy a oce cbaDce oluy releue of volatiJea or semivolatiJes and,
even if such a reIeue did occur, . would onJy be . eat ud 01 \'CI)' brief duration (because the ac:tiviry tbat
prOduced the reJcue would be stopped ud modified approprialely ifa sipificut air emission, based upon
specific: stlDdarck coataiaed in the Health a. Safecy PIaa, was detected by the contractor's air monitoring
spel"imliu). The AnDy bu sipificaat aperieace with the coutruc:tioa 01 recbarae treac:hea, extractioD aDd
reinjectioD weDs, in which coastructioa is similar to that Dec:euary for the emplac:emCDI of u iD.situ vapor
extradion system, ud bas DOt aperieac:ed uy problems &om air emisaioas duriq c:oastrudiOD of such facilities.
Subsurface facilities contemplated by this IRA are similar in aahlre to these, ud emiuioDl problems arc not
8.3 AcrION-SPECJF1C ARARa
Description
(11111<::02-4100) (11/21/19) (RNA)
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Woodward.CIyde Consultants .
anticipated. The site-specific Healtb & Safety Plan will adequately address these CODcerns. This plan to
developed (or use in the IRA will detail operaLioDaI modifications to be implemeDted in the eveDt monitoring
detects specific levels o( such emissions.
The National Emissions Standards (or Hazardous Air PoUuta.ats (NESHAPS) were evaluated to determined
whether they were applicable or relevant and appropriate, to apply in the CODte.x1 o( COnstruCtiOD o( this IRA.
These standards were Dot considered- applicable bcause they apply to stationary sources o( these poUutants,
Dot to constructioD activity. These standards were Dot considered relevant and appropriate because they were
developed (or manufacturing processes, which are significantly dissimilar to the short-term constructiOD acti\iry
cODtemplated by this IRA. However, the substantive provisions "'40 CFR Part 61, Subpart V concerning
NatioDal EmissiOD Standard for EquipmeDt Leaks (Fugitive EmissiOD Sources), particularly those substantive
f '"',
provisions found in 40 CFR S S 61.242-1- 61.242-11 are coDSid.erectr~levant and appropriate to apply to this IRA.
V ",,'''-
" ".
,.// 'y'
The provisions o( 40 CFR 50.6 will be coDSidered fti!cvant and appropriate. This standard ,is Dot applicable
because it addresses Air Quality CoDtrol Regioas...,w~~ '~ areas sigDifica.atJy larger than and differeDt (rom
the area o( CODcerD in this IRA. Pursuant to this regw~ti'there will be D~~cuJate mat!cr)ansported by
air from the site tbat is in excess o( 7S mia~ams per ~ter (annual ge4)m~~ me~j aDd the standard
o( 260 micrograms per cubic meter as a ds~-U~ur CODceDtr~' D will DO( bC'Q'ae,"ed more than once
\ \ -.., ""',
per year. \,,_/ , ~
\ / \,\/ /,-/
. .....-....., , , ,.
Worker ProtectIon ,./ /""\ '\ \ .' ~... <.
/,. . L - , ,
,. / ) ---.., "
The prcMsioas of 29 ~]I).,~le '0 --..... ~I!«ause lIIese prcMsioas specifically
address bazardous substance .~~ operatioQS (""d~'"1:mIIprtbeDSive EnvironmeDtal Response,
CompensatiOD and. . . d ~. (CER' II be Doted thai these activilies are currently
goveroed by 111& ~.~ II 29 CFR,l9J~ e lime IRA aetMty -
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Colorado Air POUUtiOD CoDtrol CommissioD RegubtioD No.1, 5 CCR 1001.3, Part III(D){2)(b),
CoDStrucUOD Activities:
a.
Applicability. Attainment and NODattainmeDt Areas
b.
.
GeDeral RequiremeDt . Any owner or operator engaged in clearing or leveling of la.nd
0:' owner or operator o( laad that has beeD cleared o( greater than ODe (1) acre iD
DODattainment areas (or which fusitM partjcu1ate emissioDS will be emitted shall be
required to use a1J available and practicaJ methods which are technologicalJy feasible
and ecoDomicalJy reasonable iD order to miDimize such emissioDS, in accordance with
the requiremeDts o( SectioD ID.D. of this reguJatioD.
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Applicable EmissioD LimitatioD dDid~liDe ~&ih the 20% capacity a.nd the no off.
property transport emission limf(atioD guideliDes S1tai1 apply to CODStructiOD activities;
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except that with respect to sO~Ces or activities associated with coDStruction for which
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there are separate require_nu 'Sa forth iD this regujatioo. the emissioD limitation
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guideliDes there specified ~"lRPlkable to such sour d activities s~ evaluated
(or compliaDce with the reqW;cm;ob, of SectiOD .~. this ,e'~~tioD. (Cross
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RefereDce: SUbScct\
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above 7,rJ1J feet (mean sea level), any air coDtaminant for a period of 10 consecutive
seconds, which is of a shade or density as to obscure an observer's vision to a degree
in excess of 50% opacity.
c.
Diesel-powered vehicles exceed.i.o.g these requirements shall be exempt for a period or .
10 minutes, if the emissions are a direct result of a cold engine start-up and provided
thc vehicle is in a stauoDat)' posiUOD.
This standard shall apply to motor vehicles intended, designed, and manufactured
primarily for use in carrying passengers or"Wgo On roads, streets, and highways.
IZ .
The foUowing performance, desip. or adioD-specifiC State ~iI ~'pplicable to this portion of the IRA and
i~ ~or~ stringent than any applicable or relevant and a~~op~ate Fedc:r~~dard, requirement, criterion or
limItation: //
. Colorado Noise Abatomeol S"'''ZQ~ 25-12-103: /)
a. Each activity '0 ~'his ani~~ sballbe -0d.' . maooo' 50 thai
any DOise prod~ced--ii::;'Ot"~ooable da..tQ intermitt .,beat (requency, or
sbrillDess. Sound l~lI.or lIoiSe--ndiatiog fr~ I ~at a distance of tWenty-
five (ee~ or more the}'~I'Q~ in excess of the ~}.4tabiis1red (or the foUowing time
peri~.;;iioDes shalt ~nsutute ~ facie meleDa: that such DOise is a public
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d.
b.
ID the hours beCWCD 7. . IDd the .. 7:00 p.m., the DOise levels permitted in
subsecboD (1) of this secDoa may be iDcreued by tCD clb(A) for a period of not to
ac:ced fifteeD .mata ill IDY oac.hoar periocL
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Periodic, impulsive, or shrill noises shall be considered a public nuisance when such
noises are at a sound level of five db(A) less than those listed in Subpart (a) of this
section.
d.
Construction projects shall be subject to the maximum permissible noise levels specifiep
for industrial zones for the period within which construction is to be completed pursuant
te any applicable construction permit issued by proper authority or, if DO time limitation
is imposed. for a reasonable period of time for completion of the project.
For the purpose of this article, measuremt'UU with sound level meters shall be made
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when the wind velocity at the time aDdp~ce of such measurement is not more than
five miles per hour. (/'" ~"."
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In all sound level measurement... consideratio;'Yall be given to the effect of the
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ambient noise level c:reatelf~ the encompassing noise of the environment from a\l
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sOurces at the time aDd~-Jf ( sound level measurements.
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In ,ubst..tive fulfillme.' .CColorado Air ~ ~ ~~. Re~/~ will employ
the Specif..d methods Cor miDimiziog emissWa CrciorlocI~ eq~~~o. acti,itie,. In
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substantive fulfillment of Colondo's Diesel-Powered Vebicle Emissioa StaDdafi!st-.ao diesel motor vehicles
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associated with the constructio~ operaftd'iD maDD~will produce emissions in excess of those
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'pecified io th... ""clards./V~. / ~,~ \)
The .oise levels pertioe.~~cIioo adivicy ~~It.s:-secli" 2S-U.l03 wi1I he attained in
accor~u~ ,7' ~~.~
e.
f.
Since small IIDOUDLS . pated from the treabDeDt system, the Army will treat the
provisions of Colorado Air PoUUIioa CoDuoJ R No. 3. SccIioa IV (0)(3)(1), u relevaat aDd appropriate
and will use bat prldica1 coatroI techaolOlY' . replatioa is DOt applicable because the IRA treatment
system wiD DOt be a major statioaary source, u defined by that rqulatioa.
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Wetlands IrnDlic.ations
Through estimauoo of the generaJ area where any system would be located., tbe Army does oot believe lhar any
wetlands could be adversely affected. However, until a fU1aJ design is selected and a fU1aJ siling decision made.
ir cannot be defwuvely determined that 00 impact 00 wetlands will occur. If the finaJ site selection and/or
design results in an impact 00 wetlands, the Army will review the regulatory pro..i.sions identified as ARARs
above coocerning wetlands impact and other appropriate guidance, and will proceed in a manner consistenl II.ilh
those provisions. Coordination will be maintained with the U.S. Fish and Wildlife Service coocerning any
potentiaJ impacts 00 wetlands.
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There are 00 actioo-specific ARARs that pertain to the eXCavauooo(sOiJ, during the construction of this
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treatment system. I I
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EPA is currently developing ,wdaoce conceroing,.,~~ Disposal Restrictions (LDR), particularly their
' applicabiliry to CERClA remediaJ actions. While g\U~Cc,is limited, the ~has not, at ,this "time, made a
determinatioo that aoy listed waste subject to~ will be )rei?t in the in1Jue~~ or~iJ ~emoved by this
IRA. More listings are scheduled to be ~~dP~ the i.mpl~ of tl.1s ~ ~d the Armv will
review these as they are released. If it is det~iI!eJ t6ar.Gsted wast~ ~ ~~~~ will act in a m~ner .
consistent with EP A guidaoce for the manageiaeat of such within the CQDt~ otCDClA actions. '
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Although removal of soil fr~ .f.'). ~; ;;'.Imem ~ ~ be'l~ed is . T1IC, ..1 .. ARAR, "
\l,iU be performed in acco~~ the pr lures lei r~,ch ~ ~ Tuk No. 32 Technical Plan, Sampling
Waste Haodling . (Novembf.r 1~.~, EPA's J.91r l~mCIDoraadum regardiDg -EPA Regioo VIII
Procedure for H" ~ria1s~ DriDinf;'Trea~ 'OD aDd Decontamination during CERCU
' / ....., "
RI/FS Operati' 'at the R MOUDtain~.. 'S~'~er Cd by excavation during the course of this
IRA, either at ee, may UfDed to the~tiOD Crom which they ori&inated (i.e.. last out,
first in). AzJy mate' aft mR D of baalit1i", that are suspected of being contaminated
(based OD field screeAiDa . UCI id . the refuCDCed document) wiD be properly stored, sampled,
aaaJyzecl., aDd ultimately disposed u CERCIA us WUtea. u appropriate.
Land DisDOsaJ Restrictions and RemovaJ of Soil
For material daermiacd to be hazardous waste resu1tiq from coastructiOD acUYitiea, subsrutive Response
Conservation IDd RecoYery Aa (RCRA) prOYisiou are applicable to their mauaemCDt. These substaotive
provisioDS include but are DOt limited to: «) CFR Pan 262 (Subpart C, Pre-Truspon Requirements), 40 CFR
part 263 (Traasponer Stedards), aDd 40 CFR Pan 264 (Subpart I, CoDtaiDu Storage aDd Subpart L. Waste
(1ll11c:m...l00) (11/21/19) (RMA)
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Piles). The specific substantive standards applied will be determined by the factual circumstances of the
accumulation, storage, or dispcsal techniques actually applied to any such material.
Soil Treatment and Di$posal
The proposed remedial action does not contemplate the onsite or offsite disposal of soils or contaminated
material, other than resulting Crom construction activities, since vapor extraction Crom the soil is intended, rather
. than excavation and disposal of soil.
8.4 COMPUANCE WITH TIlE ornER ENVIRONMENTAL LA.WS
: ../
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As is evident from the various portions of this document, this IR..\.w~prepared in substantive compliance ~ith
. .. '" ,
40 CFR 1502.16 (the regulations implementing the National ~wonmeDta1 Policy Act of 1969).
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9.0
SCHEDULE
The Draft Implementation Document is scheduled for completion on July 31, 1990. The construction scbedule
will be contained in the Draft Implementation Document for this Interim Response Action (IRA). This
milestone has been developed based upon the rlDal Assessment Document and the assumption that no dispute
resolution will occur. If events that ne~ssitate a schedule change or extension occur, the change will be
incorporated in accordan~ with the Federal Facility Aireement.
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10.0
CONSISTENCY W1TIi THE FINAL REMEDIAL ArnON
The Federal Facility Agreement states that all Interim Response Actions (1RAs) shall "to the maximum extent
practicable, be consistent with and contribute to the efficient performance of Final Response Actions" (paragraph.
22.5) .
The alternatives assessment criteria (WCC 1989) were used to evaluate the alternatives. The selected
alternative, by providing significant interim remediatioD of a source of coDtamination. will be consistent with any
"
Final Response Action. ."
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REFEREN~
Ebasco Services. IDc. 1988. July. FIDal CODtaminalioD AssessmeDt Report, Site ~, Motor Pool Area, Version
3.1, Task No. 38. RIC 88196RU.
Ebasco Services. IDc. 1989. May. Proposed Final Remedial lDvestigalioD F"mal Report, Vol. XII, WesterD Study
Area, VersiOD 3.2. RIC 89166R03.
Woodward-Clyde Consultants. 1989. rmal AlterDalive AssessmeDt of Interim Response Actions (or Olher
CODtaminatioD Sources, Motor Pool Area.
/",
Woodward-Clyde Consultants. 1989. rmal Results offield and Labora«ory Investigations CoDducted to Evaluate
IDterim Response Actions (or Other CoDtamiDalioD Sources. ./1 (
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SPECIFIC COMMENTS
Comment 1:
Response:
Comment 2.:
Response:
Comment 3:
Respoue:
P. ~1 Selection eiteria. This page identifies 7 of 9 alternative u~u"'ent eiteria that ihould
be used to compare aDd contrast alternatives. The document, however, does not use the criteria
for alternatives sclcaion. Only reduction of toxicity, mobiliry, aDd volume is addressed ill aDY
detail. Evaluation of alterutiYes ihould be based upon. but not limited to, the criteria' ill .
Section 22.6 of the FF A
The Decision Document is intended to preaent a brief summary of the detailed alteraatM
evaluation conducted in the IRA Alteruar.u "j~'-ent. The tell of the DecisiOD Document
has been revised to better disaIu the 0YeraI1 protecboa of humu health aDd the environment.
The other criteria listed in Sectioa 3.0 are ~ltd iD this document. The Army Illumes that
the other two criteria the EPA ia rcfcrriDa to are State (Support Alency) ApprovaJ ud
CommUDity Ac.c:eptaace. These criteria are addrcased durina the elleuM re-.icw process for
this document
P.4.2 la-Situ Vapor Extraction. This ia a co"t.",i"."t CODttoi ud treatment alternative that
could result ill extraction of aD uUaown quutity of COftt.",i".,,~s ud at the same time be
consistent with (or Dot preclude) uy fiDal remedy. It is a aood aIIernatiYe OD that basis.
In-situ vapor emacdoa is a Yiable alterutiYe far the removal 01 TCE from the vacbe ZODe.
The vadose zone mlY DOt be the ~dil\l source 01 IJouadwa1cr ~t.",i".tioa (See Geaeral
Comments). If the major source oflJOUDdwatet CQftt.",i-tioR ia DOt Crom percolatioa of water
throuah the vadose zone but rather I CODCrlllrlted pocbI of TCE It the base of the aDUYium,
thca m.um Ylpor emadiaD will DOt be III dectM aItenwM far preYeDtiq further miavatioa
of TCE Crom the source uea iD the IJOUDdwatet. Thill, combiDaDoG with the sroundwater
trca1ment system is appl'opriaIe.
Agccd.
P. 8-1 The DecisioD Document aecda to establisb a bca1th-bued ItIIIdard far TCE air
emisaiou. If the haJtIa.based ItIDdard CIDDOt be otberwiIc ~ fIexibiJity UouId be
specified iD thc Decisioa Documall far the vapor a&naioa _iUiNt coatroIl)'IICID to be
.,supplemwed willa a de8trucIioD - cIuriai the daip.....
The FIDII Dec:isioa DocamCDt 8dcIreues daiI matter.
(......1') (CIOIoDGttIS,.,.uG') (81'1~
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COMMENTS
CommeDts 1:
Respoase:
CommeDt 2:
Respoase:
CommeDt 3:
Respoue:
Commear 4:
Response:
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Woodward.CIyde Consultants. .
RESPONSE TO ~ATE OF roLORAIXYS ro~
ON PROPOSED DFOSION DOCUMENT
FOR OTHER OONTAMlNATlON SOURrP.~ IRA
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Response:
Comment 2:
Response:
CommeDl 3:
Respoase:
Woodward-Clyde Consultants
The response actioD designed specific:aDy for the Motor Pool Area foc:uses 011 the czttactioD of
TCE Crom the soils. Groundwater treatment is intended to be provided by the IRA for the Rail
Classification Yard, and groundwater trc.atment AR.ARs arc contained in the F'mal Decision
Document for that IRA. The specific standards themselves have also been listed in the Final
Decision Document for the Motor Pool Area IRA.
P. 8-1, para. 4: The Army stales thai the StaDdards in 40 C.F.R. pt. SO were Dot determined
to be applicable, relcvaD1 or appropriate, IiDce the rqpoD -is awkedJy ~ic.cimil.ar !rom the area
. . . affeaed by the operation of the . . . vacuUID blower.- this is an inadequate rationale for
not determiDiDa 40 C.F.R. pt. SO reJcvu1 aDd appropriate. The NCP state&, 1r)equirements
may be relevaDl and appropriate if they would be 'applicable' but for jurisdictiooal restrictions
usoNted with the requiremeDL - 40 c.F.R. I 300.6. The pOUDd water iD the motor pool area
, contains both VOCs aDd lead, aDd therefore the staDdards iD 40 C.F.R. pt. 50 dea1iD& with those
contaminants apply. ID additioa. Colorado replatinu, S CCR 1001-7, repiatioD 7 (V0Cs) and
S CCR 1001-10. regulation 8 are more striDgeDl thu the federal requirements. Therefore the
ARARs analysis should be expanded to iDclude the state regulations.
The Army does DOt believe thai the ItaDdarcla atablished UDder 40 CFR Pan 50 are either
spcdficalJy applicable or releVlDt aDd appropriate to this IRA activity. ~ staled iD the
document, the area for which these IWldards were developed. Air Quality Control Rep
(AOCR), are suIW8"ti..aUy dic.ci",il.ar !rom the lIDaD area which c:u be affected by the operanoD
of this treabDeDt system. Specific staDdarda dIMIoped far the ambient air oflarp areas such
U aD AOCR arc DCithcr rdcYu1 DOl' appropriate to apply u apeci6c emiuinn. IimitatiODI to
a source such U thai coDtempll1ed iD this IRA. Far aample, the apccific IWIdard for carbon
monoxide foUAd iD 40 CfR Pan 50 is DOt pDUaDy applied by replatory qeDCia to iDdividual
emissions from automobile tailpipa, but to the ambieD1 air iD aD AOCR.. Tbae IWldards are
Dot developed for apecific emisaiou IOUtCCI ud arc DOt appropriate to apply to IudI apecific
sourcca. The f"1DIl Decisioa DocumeDt rdJccu the AnDy'. approach to uWc;p.ated TCE
e~i..io- from the wpar auacsioa.,uem. No state I&aDdard wu ideDtified wbic:b specificaDy
addreued TCE emiuiou !rom I1ICb 1)'Itau. 1\e State, aIoa& with EP A aDd Shell, is expected
to participate ia the daip ad implem~.tW. ~ dais IRA treabDeDt l)'Item ud prcMde
,.Mu,wl iDpuI bued upoa ill cxpaicDcc ad bowIc.dF reprdiDa dais treaUDCD1 to IIIiIt iD
de~ the IpCCific deajp ad ~iuVw 1iIIIIit~
P.8-2. para. 2: 1\e AnDy atel thai the IIaDCIInk fOUDd iD 40 c.P.R. I 61 ~ were
- eaaFA-ed ~. reJewDt ar approsIriIIe. 1\e AnDy IbouId ~.id.. NESHAP.
reIevut ud approprialc if the ~t.allli"."q IUbjcd to NESHAPS arc emitted ia qu,.tities
coatemplatcd by tbe rep1atica
NESHAPS are pro1:C11 aped&c ad IiDce tbe IIaDdarcII eont-:-.cI iD thole repIatiou are
developed aped&eIny far proccIICI wbicIa arc 10 4J;..nn:r... to tbaI iDleade4 far thia IRA
treabDeDt I)'IteIII, they arc aeiIhcr rdnut DOl' .... iate to apply iD tbe caataI of thia IRA.
~Jf) (c;:ICtoOII»fft/'IfA1UG') (8"1'1).11
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